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bleeding brakes

Discussion in 'Technical and Troubleshooting Torque' started by rubenastley, Mar 3, 2012.

  1. hey guys, i recently cleaned out my front caliper pistons and all the brake fluid leaked out. my master cylinder is empty and there is no pressure in the lever. I reverse bleed the brakes using a syringe and pvc tube. it still does not have pressure, whats the go now? sorry im very new to this stuff... someone told me about bleeding from the master cylinder through the banjo bolt? my bike is a cbr250rr with nissin calipers

  2. Fill the master cylinder and bleed through the bleed nipples, wich is the "normal" way to bleed brakes. If you do it properly it might take a little while but you should get good feeling, unless there is some other problem.
  3. After I bleed mine normally I leave the top off of the master cylinder and tie the lever (so the brakes are on) to the bars. Leave it for a few hours or overnight and any trapped air will make its way back up the line and out. Works everytime for me. Bear in mind this does give the fluid chance to absorb moisture from the air so maybe overnight isn't the best option unless you are really desperate.

  4. if you reverse bled and there's no air in the line but you have no lever pressure, then yeah you need to bleed the master.
    quite simple really, just squeeze the lever as you do when bleeding at the brake calipers, except you crack the master cyl banjo bolt just enough for any trapped air to escape (maybe 1/8 of a turn)
    i suggest jamming a rag in there somehow to collect the fluid, saves cleaning things up later
  5. i work in the automotive industry, and my message to you is if you don't know what you are doing with brakes, then don't touch them. If they fail, you crash and possibly die, or you could run up on a footpath running over a child and kill them. Do you get where i am coming from :soapbox:
    • Like Like x 1
  6. lets just say i've fixed them myself and happy with this learning experience :]
  7. No probs, i am glad you got it sorted. :)
  8. Glad you got your brakes working again.
    I can see where Blue's coming from.
    Be very careful when working on your bike (not just the brakes). Maybe get someone who knows to show you first so you can confidently do your own work.
    Brakes aren't the only crutial part of a bikes' safety, pretty much everything is!!!
  9. Stopping without brakes hurts :)
    I would be giving that front a little tester for resistance for a few days. As in make sure at all times it has pressure at least...some resistance in the lever.
    If I don't have a speed bleeder I still pump through the master but let gravity do it's work for at least another half a reservoir. Therapeutically way to drink a beer too.
  10. the gilles tooling sponsors do an awesome brake bleeder, stahlbus, got some on my fireblade, heaps easier.